An example is the root-to-leaf path 1->2->3 which represents the number 123.
Find the total sum of all root-to-leaf numbers.
For example,
1
/ \
2 3
The root-to-leaf path 1->2 represents the number 12.
The root-to-leaf path 1->3 represents the number 13.
Return the sum = 12 + 13 = 25.
java code:
/**
* Definition for binary tree
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
int res ;
public int sumNumbers(TreeNode root) {
// Note: The Solution object is instantiated only once and is reused by each test case.
if(root == null)
return 0;
res = 0;
sumnum(root,0);
return res;
}
public void sumnum(TreeNode root, int tmpsum)
{
if(root.left == null && root.right == null)
{
res += tmpsum * 10 + root.val;
}
if(root.left != null)
{
sumnum(root.left, tmpsum * 10 + root.val);
}
if(root.right != null)
{
sumnum(root.right, tmpsum * 10 + root.val);
}
}
}